Why is my gun jamming? (H&K USP .40)


kingofthedemo

New member
Hey guys, I bought a used H&K USP .40 in seemingly good condition. I took it to the range and put a little over 120 rounds through it and I experianced two jams. Both jams happened as the last round was fed through the magazine into the chamber, Since it jammed both times on the last round, do you think that it could be caused by the magazine spring being to week to push the last round into the chamber?

If so should I buy a new magazine or just the spring, and where can I buy springs from? Any advice would be great, I'm kinda depressed about the jams , because I just bought this gun and I thought that I would not have this problem with an H&K.
 

The mag is the first thing I would suspect. Can you describe the jam in more detail. Where is the bullet getting stuck?
 
The mag is the first thing I would suspect. Can you describe the jam in more detail. Where is the bullet getting stuck?

Well I will try and describe it the best that I can... The bullet was at an upwards angle jammed inbetween the magazine and the chamber with the slide held slightly open from the obstruction, almost as if the bullet was stuck as it made the transition from the magazine to the chamber. This only happened as the last cartridge in the magazine was fed.

Thanks for the help guys!
 
If you don't mind the 10 round mag, I've found H&K manufactured mags at Cheaper Than Dirt for the USP 40 for $10! These were new, just in the 10 round variety.

Hey, just out of curiosity, what brand of ammo were you using?

Wow, $10.. I think I'll do that thanks! I was using Winchester FMJ .40 S&W.
 
It may, indeed, be the magazine spring and Wolff is the best. It also may be that the magazine is slipping from the frame. Is it only one magazine or all you have? Whack the bottom of the magazine when you get such a jam and if that clears it it may be the magazine catch on the magazine is worn or the catch itself.
 
First thing to do when you have feeding problems would be to swap out the magazines. They all might look identical, but you'll be surprised what a tiny defect can do. Be sure to mark your magazines so you'll know that you're actually changing them out. Once you've determined that it's not a magazine problem, then I'd check out the ammo. Different bullet types could be an issue with certain firearms. Many semi-auto pistols develop a "dislike" for certain ammo. It's important to know that whatever ammo you're using feeds smoothly and functions properly in the firearm.

In your case, it sounds like a problem with the magazine spring. When purchasing a pre-owned firearm, be prepared for all kinds of surprises. If possible, have a competent gunsmith or properly trained armorer examine the pistol. I've seen cases where the wrong spring was used in a magazine. Simple fix for your situation would be to swap out the mags. If this fixes the problem, great. If not, then it would need to be checked out further.

Good luck!



gf
 
Change mags

You have a magazine generated FTF. Dont just change the spring. It could be lip config, follower profile, spring or a combination of the three. Here is how you fix it.

1. pad the jaws of a shop vice with leather to prevent marring
2. place the magazine in the vice checking with a square to make sure it is perfectly square
3. close the vice until the magazine is less than .250 thick
4. load a new magazine in the weapon and head to the range.

I suffered a similar issue with a mag for my USP 45. The above sequence fixed it quick fast and in a hurry.

The padding is not for the magazine but for the vice.

Never trust a magazine in a combat situation that has given you the least bit of trouble.

Mags are cheap Life is not!
 
Marking the magazine is very important. Especially if you are going to follow Festus' detailed method of eliminating the problem. That would be +1 for you Festus.
Having said that my question is other then nail polish, (No it's my wife's!) do you have any suggestions for marking the magazine? Is there a commercial product specifically for this?
Thanks all.
 
Marking the magazine is very important. Especially if you are going to follow Festus' detailed method of eliminating the problem. That would be +1 for you Festus.
Having said that my question is other then nail polish, (No it's my wife's!) do you have any suggestions for marking the magazine? Is there a commercial product specifically for this?
Thanks all.

They sell paint marking pens in office supply stores, you could use spray paint from home depot, the possibilities are endless. My suggestion for marking magazines would be nail polish. Take your wife's favorite color, or you can do what I do and walk in to your local Wal-mart, Walgreen's etc., and grab the first bottle of nail polish that's bright and jumps right out at you. I will use the same color nail polish to mark all of the magazines that I put into service at the same time. If I pick up a couple of more mags a year later, they get marked with a different color. This helps me figure out when it's time to retire a magazine. How you choose to mark the magazines is up to you. I use a *, **, ***, etc. pattern on both the floor plate and the base of the magazine just above the floor plate. In the event that one or more of my markings get rubbed off, I could look at the markings on both locations to figure out which is correct and re-paint as needed.



gf
 
I used to have exactly the same problem as you .. then when we went for our CCW, I brought my gun and it jammed on me twice. My instructor looked at it and immediately said that I should have to see a machinist about it. He also advised me to change the Slide catch spring and the slide catch. The spring cost $1.00 and the Slide catch cost $10.00. Anyway, my husband piled a little bit of the entrance to where the bullet enters the hole and changed the parts, as I mentioned above and we had never had any problems since. As if it did not happen. Have someone look at your gun...
 
Thanks!

Hey I just wanted to thank all of you who have posted, the info in this thread has been very helpful to me, You guys have given me some good insight and some really creative ideas, I appreciate it!
 

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